The Treasury Department poured $83.6 billion into Fannie and $61.3 billion into Freddie to cover losses on the trillions of dollars' worth of mortgage-backed securities they own or guarantee. While that bailout money helped put a floor under the housing market, the two companies have still been shedding money -- with billions of additional losses predicted in coming years.

Last month the Federal Housing Finance Agency (FHFA) ordered both companies to delist from NYSE, saying the decision was based on the weak stock price for both companies, not due to any change in condition at the firms or outlook for their futures.

FHFA and its predecessor agency have overseen the operation of Fannie and Freddie since September 2008, when they were both placed under conservatorship, a form of control similar to a bankruptcy process.

Despite the companies' problems, Fannie and Freddie are still a main source of funding for mortgage lenders. Without the pair of firms, lending to home buyers would have completely dried up.

At the close of trade on their last day on NYSE, Fannie (FNM, Fortune 500) shares were off 17% at 25 cents, and Freddie (FRE, Fortune 500) was down 5% at 34 cents.